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| United States Patent |
5,326,646
|
|
Nakashima
, et al.
|
July 5, 1994
|
Syncronizer ring having a spray-coated film of a wear-resistant brass
material
Abstract
A synchronizer ring comprises a ring body having a sliding portion, and a
directly spray-coated wear-resistant film formed on a surface of the
sliding portion. The film is made of a wear-resistant brass alloy which
comprises Cu, Zn and at least one element selected from the group
consisting of Al, Mn, Fe, Ni, Si, Co, Cr, Ti, Nb, V, Zr and Mo. The
spray-coated film exhibits good wear resistance and good bonding strength.
| Inventors:
|
Nakashima; Kunio (Toyama, JP);
Hosoda; Masao (Toyama, JP);
Yago; Wataru (Toyama, JP);
Inagaki; Kazuyuki (Toyama, JP)
|
| Assignee:
|
Chuetsu Metal Works Co., Ltd. (Toyama, JP)
|
| Appl. No.:
|
984940 |
| Filed:
|
December 4, 1992 |
| Current U.S. Class: |
428/561; 428/546; 428/547; 428/551; 428/552; 428/553 |
| Intern'l Class: |
B22F 005/08 |
| Field of Search: |
75/157.5
148/433
192/70.15,53 F
428/552,561,562,563
|
References Cited
U.S. Patent Documents
| 4191564 | Mar., 1980 | Hirao et al. | 75/157.
|
| 4597484 | Jul., 1986 | Takiguchi et al. | 192/70.
|
| Foreign Patent Documents |
| 56133433 | Mar., 1980 | JP.
| |
| 6134154 | Jul., 1984 | JP.
| |
| 6280243 | Oct., 1985 | JP.
| |
| 6280244 | Oct., 1985 | JP.
| |
| 63157825 | Sep., 1986 | JP.
| |
Primary Examiner: Walsh; Donald P.
Assistant Examiner: Greaves; John N.
Attorney, Agent or Firm: Flynn, Thiel, Boutell & Tanis
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A synchronizer ring which comprises a ring body having a sliding
portion, and a directly spray-coated wear-resistant film formed on a
surface of the sliding portion, said film being made of a wear-resistant
brass alloy which comprises Cu, Zn and at least one element selected from
the group consisting of Al, Mn, Fe, Ni, Si, Co, Cr, Ti, Nb, V, Zr, and Mo.
2. The synchronizer ring according to claim 1, wherein said alloy
comprising 50 to 80 wt. % of Cu, 20 to 45 wt. % of Zn and 0.1 to 10 wt. %
of said at least one element other than Mo which, if present, is from 1 to
50 wt. % of the alloy.
3. The synchronizer ring according to claim 1, wherein said wear-resistant
film is formed on an inner peripheral surface of said ring.
4. The synchronizer ring according to claim 1, wherein said wear-resistant
film is formed on an outer peripheral surface of said ring.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a synchronizer ring which is adapted for use in
transmissions of vehicles which require high torques.
2. Description of the Prior Art
As is known in the art, synchronizer rings have been usually fabricated
using only a wear-resistant copper alloy. With the transmissions of
vehicles, such as large-sized vehicles or sport cars, which need high
power and high torque, the synchronizer ring has been fabricated wherein a
synchronizer ring body is made of an iron material and a wear-resistant
film or layer is formed on the surface of a sliding portion of the ring
body. By this, a high wear resistance is imparted to the sliding portion
of the synchronizer ring. This has been realized in the following manner.
1. Mo which is known to have a high wear resistance is spray-coated at a
sliding portion.
2. A mixture of a wear-resistant aluminum alloy and Mo is spray-coated at a
sliding portion.
3. A wear-resistant part is bonded to a sliding portion mechanically or by
welding.
The Mo spray-coating procedure has been widely performed at present for
application to large-sized vehicles. However, Mo is very expensive,
resulting in the high production costs of the ring article.
The spray-coating of a mixture of a wear-resistant aluminum alloy and Mo
has now been used in some synchronizer rings. This is because Si contained
in the wear-resistant aluminum alloy is liable to impede wettability with
a matrix body on spray-coating, thereby lowering the bonding strength of
the coated film. In fact, limitation is placed on the applications except
for large-sized vehicles.
With wear-resistant parts being bonded mechanically or by welding, a
wear-resistant part has a sliding surface shaped in the form of a ring and
inserted into a synchronizer ring body. Thereafter, the part may be fixed
with a pin. Alternatively, the part may be subjected to a complicated
procedure of the combination of shrink fitting, cold fitting and electron
beam welding. Thus, the fabrication becomes very complicated. In addition,
an increasing number of parts are essential with an additional number of
assembling steps, thus leading to an inconvenience from the standpoint of
production costs.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a synchronizer ring
making use of an inexpensive wear-resistant material which ensures a high
wear resistance and a stable bonding strength when spray-coated as a film
on the sliding surface of a ring body.
It is another object of the invention to provide a synchronizer ring which
has a metallized wear-resistant film formed at a sliding portion by a
simple spray-coating procedure whereby the ring can stand high load when
used in transmissions of vehicles requiring high power and high torque.
The above objects can be achieved, according to the invention, by a
synchronizer ring which comprises a ring body having a sliding portion,
and a directly spray-coated wear-resistant film formed on a surface of the
sliding portion, the film being made of a wear-resistant brass alloy which
comprises Cu, Zn and at least one element selected from the group
consisting of Al, Mn, Fe, Ni, Si, Co, Cr, Ti, Nb, V, Zr and Mo.
Preferably, Mo is added to the wear-resistant alloy in an amount of from 1
to 50 wt. % based on the alloy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic plan view of a synchronizer ring according to one
embodiment of the invention;
FIG. 2 is a sectional view taken along the line A--A of FIG. 1;
FIG. 3 is a schematic plan view of a synchronizer ring according to another
embodiment of the invention; and
FIG. 4 is a sectional view taken along the line B--B of FIG. 3.
PREFERRED EMBODIMENT OF THE INVENTION
Reference is now made to the accompanying drawings and particularly, to
FIGS. 1 and 2. In these figures, there is shown a synchronizer ring R
according to one embodiment of the invention. The ring R is of the inside
sliding type wherein the ring is slided with a gear cone along the inner
periphery thereof. The ring R has a synchronizer ring body 1 and a
wear-resistant film 5 on the inner peripheral surface serving as a sliding
portion. The synchronizer ring body 1 is made, for example, of an iron
material such as JIS G4052 SCM435H, a copper material such as JIS H3250
C6783, an aluminum material such as JIS H4040 6063, or the like. The ring
body 1 is fabricated by hot forging the material at a forging temperature
of 1000.degree. C., thermal treatments (carburization and quenching) and
machine works (lathing, machining and polishing). The wear-resistant film
5 is formed by direct spraying of a wear-resistant brass material.
The wear-resistant brass alloy used in the invention comprises Cu, Zn and
at least one element selected from the group consisting of Al, Mn, Fe, Ni,
Si, Co, Cr, Ti, Nb, V, Zr and Mo. Preferably, the brass alloy comprises 50
to 80 wt. % of Cu, 20 to 45 wt. % of Zn and 0.1 to 10 wt. % of Al, Mn, Fe,
Ni, Si, Cu, Cr, Ti, Nb, V and Zr. More preferably, the at least one
element is Al, Mo, or Fe. When present, Mo content is from 1 to 50 wt. %
of the alloy.
The brass alloy has a structure which consists of a matrix and an
intermetallic compound which is harder than the matrix. The matrix
structure consists of an .alpha. +.beta. phase, a .beta. phase or a
.beta.+.gamma. phase. The intermetallic compound has a micro Vickers
hardness no lower than 300. When the brass alloy is directly spray-coated
on a sliding portion of the ring, the resultant film becomes very hard and
resistant to wear. The direct spray coating used herein means an ordinary
spray-coating procedure such as a high velocity oxygen-fuel gas system, an
ultrasonic spray coating using an oxygen gas-mixed fuel gas, a metallizing
procedure or a plasma spray coating.
The spray coating brass alloy does not always contain Si. If present, the
content of Si is very small. Accordingly, the wettability with the ring
body is not impeded and stable bonding strength of the wear-resistant film
is attained.
Mo is preferably added to the brass alloy in an amount of from 1 to 50 wt.
% based on the brass alloy. If Mo is added to the alloy composition, the
wear resistance and the bonding strength are further improved. However, if
the content is less than 1 wt. %, the improving effect is not expected. On
the contrary, when the content exceeds 50 wt. %, any further improvement
is not expected. This is the reason why the content of Mo ranges
preferably 1 to 50 wt. %.
FIGS. 3 and 4 show another embodiment of the invention. The synchronizer
ring R of this embodiment is of the outside sliding type wherein the ring
is slidedly contacted with a cone sleeve at the outer peripheral surface
thereof. Accordingly, the synchronizer ring body 1 has the wear-resistant
film 5 formed along the outer periphery of the body 1 as shown in FIGS. 3
and 4.
The invention is more particularly described by way of examples.
EXAMPLES
Wear-resistant brass alloys having compositions indicated in Table 1 were
prepared. Actually, alloy Nos. 1, 3, 5, 6 and 7 were used and alloy Nos. 2
and 4 are shown in Table 1 only for illustration.
TABLE 1
__________________________________________________________________________
Brass alloys of Invention (wt. %)
No. Cu Zn Al Si Fe Ni Ti Mn Zr Mo Nb Cr Co
__________________________________________________________________________
1 Bal*
28 4 0.6
0.7
-- -- -- 1 -- -- -- --
2 " 26 5 -- 1 -- -- 2.5 -- 0.2 -- -- --
3 " 30 4 -- -- 1 1 -- -- -- 0.5
-- --
4 " 25 6 -- 1.5
-- -- 2.5 -- -- -- 0.3
--
5 " 30 4 1 1 3 -- -- -- -- -- -- 1.5
6 " 38 1.5
1 -- -- -- 2.5 -- -- -- -- --
7 " 31 3 1 -- -- -- 3 -- 0.2 -- -- --
__________________________________________________________________________
*100 wt. % in total.
Synchronizer ring bodies as shown in FIGS. 1 and 2 were fabricated using
JIS G4052 SCM435H material to have an inner diameter of 66 mm by
subjecting the material to hot forging at a temperature of 1000.degree.
C., carburization and quenching, and lathing, machining and polishing.
The brass alloy Nos. 1, 3, 5, 6 and 7 were fundamentally used, with or
without addition of Mo, for spray coating the respective alloys by a high
velocity oxygen-fuel system to form a wear resistant film on the inner
peripheral surface of each ring, thereby obtaining synchronizer rings of
the invention and for comparison. The respective rings were subjected to
wear resistant and bonding strength tests. The test conditions for the
wear resistance are shown in Table 2 below wherein the wear-resistant film
was formed in a thickness of 100 .mu.m.
TABLE 2
______________________________________
WEAR-RESISTANT TEST CONDITIONS
______________________________________
Number of Revolution
1800 r.p.m.
Applied Load 70 Kgf
Number of Load Application
2,000 cycles
Application Time 0.3 seconds under load
1.5 seconds under loan-free
conditions
Lubricant ATF Dexron
Manner of Lubrication
dipped to a level
corresponding to 1/2 of the
ring diameter
Temperature of Lubricant
70.degree. C. .+-. 5.degree. C.
Opposing Member SCM-22H
______________________________________
The bonding strength was determined by a tensile test of the bonded portion
according to the procedure of ASTMC633.
The results of both tests are shown in Tables 3 and 4.
TABLE 3
__________________________________________________________________________
Results of the Wear-Resistance Test
Material of
Spray-coated Film Wear Depth
Ring Body on Sliding Portion (.mu.m)
__________________________________________________________________________
Inventive Synchronizer Ring No.
1 SCM 435
brass alloy No. 1 of Table 1
80
2 " brass alloy No. 3 of Table 1
70
3 " brass alloy No. 6 of Table 1
210
4 " brass alloy No. 7 of Table 1
180
5 " brass alloy No. 6 + 1 wt. % Mo
152
6 " brass alloy No. 6 + 10 wt. % Mo
143
7 " brass alloy No. 6 + 30 wt. % Mo
131
8 " brass alloy No. 6 + 50 wt. % Mo
124
Comparative Synchronizer Ring No.
9 " brass alloy No. 6 + 60 wt. % Mo
125
10 " brass alloy No. 6 + 70 wt. % Mo
124
11 " 100 wt. % Mo 150
12 " (15 wt. % Si--Al alloy) + 50 wt. % Mo
250
13 ring formed solely of alloy No. 1 of Table 1
160
14 ring formed solely of alloy No. 7 of Table 1
310
__________________________________________________________________________
TABLE 4
__________________________________________________________________________
Results of the Bonding Strength Test
Material of
Spray-coated Film Bonding Strength
Ring Body
at Sliding Portion (Kgf/cm.sup.2)
__________________________________________________________________________
Inventive Synchronizer Ring No.
1a SCM 435
brass alloy No. 1 of Table 1
560
2a " brass alloy No. 1 of Table 1
580
+ 1 wt. % Mo
3a " brass alloy No. 1 + 10 wt. % Mo
583
4a " brass alloy No. 1 + 30 wt. % Mo
588
5a " brass alloy No. 1 + 50 wt. % Mo
590
6a " brass alloy No. 5 of Table 1
565
7a " brass alloy No. 5 + 1 wt. % Mo
583
8a " brass alloy No. 5 + 10 wt. % Mo
585
9a " brass alloy No. 5 + 30 wt. % Mo
588
10a
" brass alloy No. 5 + 50 wt. % Mo
592
Comparative Synchronizer Ring No.
11a
" brass alloy No. 1 + 588 wt. % Mo
12a
" brass alloy No. 5 + 70 wt. % Mo
590
13a
" 100 wt. % Mo 525
14a
" (15 wt. % Si--Al alloy) + 50 wt. % Mo
350
__________________________________________________________________________
1) On comparison between Ring Nos. 1 and 13 and also between Nos. 4 and 14
of Table 3, it will be seen that the spray-coated film of an alloy is
better in the wear resistance than the ring made solely of the alloy.
2) On comparison with the prior art spray coatings of Mo (Alloy No. 11 of
Table 3 and Alloy No. 13a of Table 4) and the prior art spray coatings of
15 wt. % Si/Al alloy and 50 wt. % Mo (Alloy No. 12 of Table 3 and No. 14a
of Table 4, better results are obtained in the present invention with
respect to the bonding strength and the wear resistance.
3) When Mo is added in an amount of from 1 to 50 wt. %, both wear
resistance and bonding strength are significantly improved. However, if
the content exceeds 50 wt. %, a further improvement is not expected.
4) The wear resistance of spray-coated synchronizer rings depends greatly
on the type of spray-coating alloy.
5) When Mo is added to spray-coating alloys such as, for example, Alloy No.
6 of Table 1, which are not so good with respect to the wear resistance,
the wear resistance can be improved.
As will be apparent from the foregoing, the synchronizer ring of the
invention having a wear-resistant film formed at a sliding portion has not
only a good wear resistance, but also a good bonding strength. The
wear-resistant film can be formed by a simple spray-coating method and an
inexpensive synchronizer ring can be obtained.
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